1. Field of the Invention
This invention relates to an operator mechanism and to a ratchet mechanism for effecting reciprocal lateral movement of an element of a geared drive train in a door, gate or barrier operator and relates particularly but not exclusively to such for use in domestic operators.
2. Present State of the Art
In operator mechanisms for doors, gates or barriers, it is known that if the power fails, the door, gate or barrier cannot be manually opened due to the mechanical advantage created by the drive train between an electric motor and the door, gate or barrier. In such cases, a release mechanism has been provided to separate the door from the drive motor so the door can be manually opened. Some release mechanisms for sectional/tilt doors are as simple as removing or displacement of a coupling pin at a track carriage, whereas in some other release mechanisms for roller doors, a clutch is provided. There are some proposals for a ratchet operated clutch mechanism where the clutch can be rotated in one direction to effect drive engagement where the ratchet returns to an initial position so that when the ratchet mechanism is next operated, drive will be reconnected. Typically, such ratchet mechanisms operate by a pull string cord so that a first pull effects drive engagement and the second pull effects drive disengagement.
In some known operator mechanisms, there is provided an element of a geared drive train mounted coaxial with at least one drive axle of one gear within the geared drive train. The element is moved in one direction to effect drive engagement and moved in the opposite direction to effect drive disengagement. Thus, in one lateral position drive in the geared drive train will be effected to permit the operator to open and close the door, gate or barrier, and so that in another lateral position drive in the geared drive train will be disconnected. In that event, the door, gate or barrier can be manually opened. One example of a door operator suitable for use with a roller door is disclosed in our prior Australian patent application no. 2008250340. The whole of the subject matter of that patent specification is hereby incorporated by reference. It should be appreciated that whilst the aforementioned prior Australian patent application is directed primarily to a roller drive assembly the inventive concept herein is applicable to use with an operator for any type of door, gate or barrier.